The present invention relates to an eyeglass lens grinding apparatus for grinding the periphery of lenses to fit into an eyeglass frame.
An eyeglass lens grinding apparatus is known and it grinds the periphery of lenses to form a bevel at which each lens is supported in the groove of the eyeglass frame so as to achieve good fit into the latter.
In lens processing with this type of grinding apparatus, it is important to determine the best bevel position with respect to the edge position of a lens which has been processed into conformity with the configuration of an eyeglass frame. This is largely dependent on the experience and special hunch of the operator and great skill has been required to form satisfactory bevels. To deal with this problem, the edge position predestined by lens processing is measured and after the bevel position that divides the edge at a preset ratio is automatically determined on the basis of the obtained information, processing is subsequently carried out in accordance with the thus obtained information on the bevel position. An apparatus capable of this automated (AUTO) processing is already in commercial use.
However, the bevel position to be determined in the automated processing is entirely up to the manufacturer of the processing apparatus and the bevel formed is not necessarily in compliance with the specifications required by the processor (who has presented the eyeglasses). To accommodate this situation, the apparatus described above is adapted to be such that the processing mode is shifted to FORCED mode and the bevel position can be altered by supplying the apparatus with the necessary information. However, it is cumbersome to adjust the bevel position in each processing cycle.
In addition, the thickness of the rim of the eyeglass frame is generally different depending upon whether its constituent material is metallic or plastic and, it often becomes necessary to alter the bevel position in accordance with the constituent material of the frame.